Obtaining sterols of high purity



March 7,-1950 H. A. VOGEL TAL 2,499,430

OBTAINING sTERoLs oF HIGH PURITx Filed July 30, 1947 Patented Mar. 7, `1950 2,499,430 OBTAINING STEROLS OF HIGH PURITY Henry A. Vogel and Roger waukee, Wis., assignors lVI. Christenson, Milto Pittsburgh Plate Glass Company, Allegheny County, Pa., a corporation of Pennsylvania Application July so, 1947, serial No. 764,886

24 Claims. (Cl. 260-397.2) y

The present invention relates to a process of fractionating and purifying sterol concentrates and it has particular relation to |a process of purifying and fractionating a concentrate of unsaponiable matter as obtained from tall oil by extraction methods.

One object of the invention is to provide a process applicable upon a commercial scale lfor preparation of relatively pure sterols from tall oil.

A second object is to separate from the unsaponiiiable matter of tall oil a fraction of saturated higher alcohols useful for production of synthetic waxes and other purposes.

A third object of the invention is to obtain from the unsaponifiable matter of tall oil a fraction which is rich in polymerized rosin derivatives.

A fourth object is to remove from the unsaponifiable matter of tall oil as obtained by extraction methods certain components which have heretofore prevented the preparation of highly .purified sterols by simple methods of crystallization.

A fifth object of the invention is to provide a' simple and economical method of obtaining highly purified sterols from the unsaponifiable matter of tall oil.

A sixth object of the invention is to provide a process of separating higher alcohols and other components of the unsaponiiiable fraction of tall oil which may be operated continuously and countercurrently.

These and other objects of the invention will be apparent from consideration of the following specification and claims.

It has heretofore been proposed to obtain the uns-aponiable matter oftall oil by a number of' different methods. Probably the most satisfactory methods heretofore proposed are disclosed in certain copending applications notably an vapplication to Christenson and Gloyer, S. N. I701,900, :filed O'ct. 8, 1946, and entitled Separation of unsaponiable matter from tall oil residues and an application to the same inventors, S. N. 704,314, filed Oct. 19, 1946, and entitled Fractionation of tall oil. The process as disclosed in the first broadly involves saponifcation of the acids of tall oil such as the higher fatty acids and the rosin acids in a distillation pitch from which a large proportion of the acids have been distilled with an alkali and the extraction of unsaponifiable matter from an aqueous alcoholic solution of the resultant soaps by countercurrent contact of the solutions with a solvent such as petroleum naphtha.

The process of the second application involves dissolving the crude tall oil soaps in aqueous isopropyl alcohol and extracting out the whole unsaponilable content with naphtha.

By application of such processes, there were obtained in solution in the naphtha., concentrations of unsaponiable matter comprising sterols such ias beta sitosterol, higher alcohols containing 20 to 26 carbon atoms in the hydrocarbon chain, polymerized rosin components and hydrocarbons. There were also present pigmentary materials and perhaps other components of uncertain composition.

In order further to purify this concentrate of unsaponifiable matter, the matter was subsequently dissolved in an appropriate solvent therefor such as alcohol or esters, ethers, hydrocarbons or the like. Upon cooling of the solutions a certain amount of purification resulted owing to seleotive lcrystallization of the sterols. However, the composition was such that completely satisfactory crystallization was impossible. Accordingly, it was found impractcable to obtain compositions of greater than 60 to 80 or possibly 85% sitosterol content.

The present invention is based in part upon the discovery that the diiculty of obtaining satis- 'factory purification of the sterols of the tall oil by crystallization methods was due at least in large measure to the presence of certain alcohols of high molecular weight, e. g. alcohols containing about 20 to 26 carbon atoms in an aliphatic chain. The invention further comprises the discovery that these higher alcohols can successfully be separated from the sterols by washing a naphtha. solution of the unsaponiiable matter, for example, with furfural which acts as a selective solvent to remove the sterols together with any polymerized rosin components and certain coloring matters. The furfural solution, having dissolved selectively the sterols, polymerized rosin cornponents and certain of the pigments, may then be in turn washed with naphtha in a second operation. In this operation the naphtha dissolves out the sterols and certain coloring matters, while the furfural selectively retains in solution the highly polymerized components. As an additional feature the resultant concentrate of sitosterol from which the higher alcohols have been removed can successfully be crystallized either with or without the intermediate treatment of rewashing with naphtha in order to obtain products of to 100% sitosterol content.

Various compositions of unsaponifiable matter containing sterols such as sitosterol and higher alcohols may be employed as starting materials for the preparation of relatively pure sitosterol in accordance with the provisions of the present invention. So long as a composition comprising a concentrate of sterols and higher alcohols is obtained as a starting, or raw product for application of the principles of the present invention, it is embraced by the broader concepts as herein described. Especially desirable compositions, however, are obtained by the saponication of tall oil or the distillation residues from the distillation or" the fatty -acids and rosin acids from tall oil and extraction of the unsaponiiable matter from an alcoholic solution of the resultant soaps with naphtha or other appropriate solvent of unsaponiable matter of tall oil which solvent is insoluble in the aqueous alcohol solutions. An unsaponinable composition vas obtained by a process such as that disclosed in Christenson and Gloyer application 701,960, led October v8, 1946,

above referred to constitutes a satisfactory material to which the present invention can be applied.

The procedure in the extraction of the concentrate, for example, may comprise the saponication of a distillation pitch or residue from tall oil containing 30 tori-0% fattyacids, 27 to 42% rosin :acids and 20 to 30% of unsaponiable components. Such pitches are s-old bythe West Virgini-a lPaper Pulp Company under the tradenarne of Tallene In the preparation of a soap solution from which the unsaponiiiable matter could be .extracted in accordance with the disclosure of the foregoing application 280 parts of distillation pitch, 9o parts of isopropyl alcohol, 24.4 parts of sodium `hydroxide and 85.6 parts of water, all expressed as parts by weight were admixed. The mixture was thenheated under a reflux condenser to the boiling point until the saponiable oonstituents had reacted with sodium hydroxide. Usually-one or two hours will be sufcient for the reaction, but vheating can be continued longer Aif so desired. Of course, excessive :increaseof the period of heating unnecessarily increases the costs.

Soaps of tall oil pitches made las above described -rnay be extracted with naphtha in order to Aremove 'the `unsaponiable matter in accordance with 'the following procedure. The above saponied mixture is diluted with waterso that a solution of l to Zoparts of the soap in isopropyl alcohol and `water Yis obtained, the isopropyl alcohol being within a range of to 36%. This solution Lmay then be countercurrently extracted with naphtha within al1-ange of l to 15 partsby volume per -part of soap solution. The extraction may be either batchwise or countercurrent and 4the temperaturelof :extraction vmay loe within a range of l5-145 e. g. 120 li'. As a result ofthis extraction aconcentrate of the unsaponiablematter in the naphtha phase is obtained. This solution may be water washed to remove water soluble impurities.

The naphtha or such other solvent as may be used may be evaporated and if desired, the concentrate may then again be made up with naphtha for treatment in accordance with the provisions of the present invention. However, it is also vpermissible to employ the naphtha solution as obtained directly from the extraction of the unsaponiable matter from the soap 'solutions.

The naphtha may also be evaporated and the concentration of sterols then dissolved in an appropriate solvent such as methyl alcohol or acetone and the solution subjected to cooling to effect crystallization. As a result-of this operation a-certain degree of concentration ofthe sterols is obtained by reason ofdilerential crystallization. However, vit is impracticable to obtain a concentration of greater than approximately '60 to'85% of Ysterols (mostly sitosterol) in the crystalline matter. The resultant impure sterol concentrate includes alcohols of long chain-length,

. 4 e. g. 20 to'26 carbon atoms and also .polmnerized 'resin components -as wellas coloring matter.

It is impracticable further to purify this mixture by direct crystallization methods. However, after the long chain (C20 to C25) alcohols have been removed by the technique presently to be described, this mixture yields readily to crystallization techniqueto provide highly purified sitosterol.

n accordance v'with the provisions of the present invention, it has been found that the long chain length alcohols can readily be removed from the sterol :concentrates before or after preliminary crystallization, to obtain a product from whichessentiallir pure sterols can be obtained by crystallization. For purposes of effecting suchiextraction, the impure unsaponiable matter constituting the concentrate 'of sterols `is dissolved -in naphtha, :such asta fraction of `petroleum hydrocarb-ons consisting primarily of vopen chain saturated compounds lboiling preferably within a range of v toabout .130 C. being preferred. This solution is then extracted with riurfural under, appropriate condtions.

The extraction may oe-conducted batchwise or countercurrently but lcountercurrent extraction is usually preferred since it is more efficient. An appropriate embodiment of :apparatus is illustrated diagrammatically yin the attached flow sheet indicated in the drawings.

The apparatus as shown includes -a colurne I to which a solutionof .talloil unsaponifiable matter containing 2.0 to 50%-of sterols such .as s itosterol, the rest ofthe mixture being primarily the long chain length alcohols, polymerized rosin components and pigmentary materials in varyingproportions may be fed as vindicated -at 1I G yfrom source yI I. Thefeedis continuous or substantially so and the sterols are admixedwith naphtha supplied through a line I 2 from an appropriate -container I3. `The feed, preferably, Lis near or some- What'below themidpoint of the column. If desired, naphtha may also 4be -fed through a branch i4 of the .line l2 into a zone near the bottom of the column I. The furfural is fed into Vthe top of the columnor near Ithe top ofthe column from a container l5 through a lline Aindicated at Il.

The unsaponilable matter .and the .naphtha may be vmade up into .solution prior to introductioninto the feed line Ill, orfthe method indicated in the drawing may be employed in which the unsaponiable matter is Amelted to form a flowable body. Alongwith naphtha, it is fed .into the line just prior to introduction into the extraction column I.

Thenaphthas employed-as solvents for the unsapon'iableima'tter vof tall oil may comprise the *JMP type containingfaromatic hydrocarbons and being of various volatility ranges, yor vthey may be of the straight chain hydrocarbon type. The naphtha .preferably should not be -of too high Volatility since highly `volatile materials would entail excessive losses by evaporation and perhaps `would even require .pressure containers lto prevent suchvloss. Excessively low volatility is also'undesirable since it would entail unduly high operating "temperatures in the distillation operations. A'boiling range of about 85 to 130 C. is to be preferred in most cases.

The furfural preferably is employed in a proportion of 3 to 140 lparts by volume per ,part of unsaponiable matter to .be extracted. The temperature of thecolumn preferablyis Within the range of about'60 to 160 F. It shouldbe lhigh enough to prevent "extensive crystallization of the sterols'in the system and yet sufciently low to prevent excessive mutual solubility of the two solvents in the system. In general, conditions will be so adjusted that 50 to 80% of the unsaponifiable material will pass into the furfural phase from column I.

The use of furfural, water saturated or partially saturated with water at the temperature of operation in the column I, is also contemplated though of course certain adjustments of the solvent ratios and/o1' the temperatures of operation may be desirable if this change in the mode of operation is employed. In general it will be found desirable to operate with furiural which is essentially water-free.

From the column I is obtained a naphtha phase or fraction which is drawn off at the top of the column as indicated at i8. This fraction includes all or most of the long chain aliphatic alcohols previously referred to and it also includes certain pigmentary materials and perhaps other constituents. This alcohol rich fraction, after evaporation of the solvents may be employed in forming synthetic waxes or for other purposes.

There is also obtained from line I9 passing from the bottom of the column a iurfural phase in which is dissolved all or most of the sterols such as sitosterol together with coloring matter and polymerized rosin derivatives of various kinds.

It will be appreciated that the sitosterol fromv the furfural phase may be employed as such in the preparation of various pharmeceuticals, though perhaps the products obtained by such process would be rather dark in color. In most instances, it is desirable to decolorize and also to remove the polymerized rosin components from the sterols. This may be readily accomplished by crystallization methods, for example by evaporating the furfural from the solid constituents then dissolving the solid material in an appropriate solvent such as acetone or an alcohol or ether or any of the common solvents of sitosterol and the like sterols and then chilling the resultant solution selectively to crystallize out the sterols. The resultant `product is still rather dark in color by reason of the presence of small amounts of pigmentary materials.

Usually it is desirable to remove the rosins or polymers of rosins and the coloring matter' from the sterol product'which has been freed of higher alcohols by appropriate extraction with naphtha. To this end, the line I9 is connected to a still 2| in which a proportion of the furfural, e. g. 1k to 3A is evaporated. If desired, this still may be by-passed by a line 22 having a valve 24. The

solution is discharged into the top of the second column (II) through line 26. Naphtha is introduced into the bottom portion of the column as indicated at 21 from an appropriate storage container 28. The naphtha may be of the same grade as that employed in column I or if desired, it may be of a different grade. Preferably, it is employed withinva range of 6 to 150 parts by volume of the unsaponiable material introduced into the rst column. Even higher proportions of naphtha in column II are permissible but of course their use enlarges the size of the apparatus required to handle a given amount of product and otherwise tends to become uneconomical. The temperature of operation of the second-column in general, will be within an approximate range of 60 to 160 F.

The furfural solution of polymerized rosins and coloring matter is drawn off through a line 29 at or lnear the bottom of the column II and may be subjected to distillation in still 3l in order to remove the furfural. The furfural may be recycled for use in column I. The product passes to receiver 30.

The naphtha solution of sterols, such as sitosterol, in a form highly suitable for further purication by crystallization methods maybe drawn off at the top of the column through line 32 and passed to a still 33 in which the naphtha is evaporated for re-use or for other purposes. The sterol fraction is drawn oif from the still and passes to receiver 31 in which it can be stored or subjected to purification by crystallization methods as herein described.

The naphtha solution of higher alcohols drawn off from column I through line I3 is also passed through a still indicated at 38 in which the solvents are evaporated to obtain said alcohols. These alcohols are passed through line 39 to a receiver 4I for storage or for further treatment.

The crystallization of the sterol fraction as obtained from the treatments previously described are essentially the same as have heretofore been suggested as being appropriate for partial purication of sterols such as sitosterol. The processes involve dissolving the sterols in any one of a large number of organic solvents such as alcohol, acetone, ether and others followed by chilling in order to crystallize out the sterols.

The present process7 however, distinguishes over those heretofore employed by reason of the fact that it is capable of producing highly pure sterols, e. g. tho-se having melting points up to 139i C. and of a ysterol content practically pure. In contradistinction, in the conventional methods of operation the production of pure sterols from'tall oil unsaponifiable matter by crystallization methods was diflicult if not impossible because the higher alcohols and perhaps other constituents tended to crystallize simultaneously with the sterols thus preventing successful purification.

The treatment of concentrates et unsaponifiable matter as obtained by extraction of said matter from soap solutions of the distillation residues of tall oil have been particularly described. It will also be appreciated that whole tall oil appropriately saponied as above described, can be extracted with naphtha to remove unsaponiable constituents. This naphtha extract may then be extracted with furfural to remove sterols, the sterol fraction being re-extracted with naphtha and otherwise treated to recover pure sterols as described for preparation of pure sterols from distillation residues.

The general principles of application of the invention has been described. The following illustrates a specic example of the application of such principles:

Example A solution of tall oil unsaponifiable matter in a low-boiling type of naphtha of boiling range 85 to C. containing 40% by weight of unsaponifiable matter was pumped into a S-inch diameter packed column of 45 ft. height somewhere near its midpoint. Furfural, dry and naphtha-saturated, was pumped in near the top of this column and fresh naphtha near the bottom of the same column. The urfural phase, commonly called theextract, was delivered to a second column, entering it near the top. Into this second column fresh naphtha was pumped near the bottom. The naphtha phase leaving at the top of this column was led through a solvent recovery system and a hard light-brown solvent-free ma-.

medirse terial was.v obtained in. approximately 6.0 yield (basis the weightof` unsa-poniiia'blev matterv used). The` material upon crystallization, yielded.'` pure white sterol crystals of 13G-138 C.. (.coriz` melt;- ing point, with a.. purity of.` better than 95% sitosterol by digitoninassay. The originalunsaponiable. matter when. crystallizedin; a similar man ner yields sterols of yellowish-brown color (dependent upon the efficiency of washingthecrystels) and a sterolpurity'of- 65.-80%

The: conditions used in the, example cited were as follows:

R atio` solvent by vol. to unsaponifable matter Vols.

CO`LUl\/[N I: OPERATING TEMQP'ER-ATURE 130 F.

Unsaponiliable mattcr-l6 48 1.0 Nepl1tha-32 A 2. 0 Furfural 200, l2. 5 Naphtha as reflux 40 2. 5

COLUItN II: OPERATING' TEYIPERATURE l3ll F.

All iurfural phase from Col. I 225? Naphtha 225 14. .0

Yields A. Expressed in per centby Wt.. ot solids showing division of" unsaponiable matter in each column:

Per cent ColumnI:

Rafnate-naphtha phase 25.4 Extract-furfural phase; 74.6, Column II:

Raihnate--Naphtha phase 83.2 Extract-furural phase 16.8`I

B. Net yields-showing the division into nal three fractions: Per centv Ranate, Col- I 25.4 Ranate, Col.. II 62.1 Extract, Col. II 12.5-

Orig. Un-l Raol saponiiiablev matter Crystalyield per cent.. 52; 8` 48; 0` Net crystal yield (base originali Unsa matter per ecn 32.8; 48. A Melting point, sterol crystals l Q 135,-136.' 5 115-120 Sitosterol content of crystals, digitomn` assay per cent" Above 95 72 In the counter-current operation of' this system, the yields of material retained in the.V naphtha phase andv in the furfural. phase in; each column are a. function of temperature; concentrationk of unsaponiahlev material present and ratio of naphtha to furfural. By far the; most important factor controlling the. distribution of, thev unsaponiabl'e matter between the two solvents in either column. is the naphtha-furfural ratio. For example, in the preferred operation. for maximum eciency and, maximum pure sitosterol recovery, the ratio of naphtha to furfural. in the first. column is 1:2.75 and the. naphtha-furiural ratio in thek second column is 1^.1:l.0. The ratio of naphtha may be raised in the first column, with the. result thatv not only the alcohols but some of the sterols will be retained by the naphtha. Such sterols are then lost for recovery and appear in the iinal alcohol fraction. Vice-versa, the furfural ratio may be increased in the iirst column with the result that all the sterols and some of the alcohols will go into the furfural phase. This would lead tov alcohols being present in the nal sterol-rich fraction. It is to be understood' thatl the yields' may bev varied at will, placing as much or as little of the unsaponiable matter into furfural as desired. The same principle of balancing naphtha-furfural ratios in the 'secondI column affects the distribution of sterols and rosin-like polymerized materials. The invention is not to be limited to the use of specific ratiosvof solvent, but for preferred operations the yields in the first column shouldl be (S0-80% extract and 2li-40% raiiinate. These yields are obtained by having a naphtha-furfural ratio between 1-:2 and 1:7. The preferred yields in the second column are G0L-90% rainate and 10-40% extract. These may be obtained by having a naphtha-iurfural ratio of between 1:0.5 and 1:2.

The process as: described above has illustrated the use of a naphtha solution of tall oil unsaponifiable matter .as a means of contacting the unsaponifiable matter with furfural. It is within the scope of this invention, and at times it may be desirable, to introduce the unsaponifiable matter into the system without previously contacting itfwith naphtha tol form a solution. Likewise, it isalso permissible to prepare a iurfural solution of the unsaponiable matter and allow this solution to be extracted" by a naphtha. The primary essential to secure the type of separation desired is' to allow the three main components, the unsaponi'able matter, the selective polar solvent, e. g. furfural', and the nonpolar solvent, e. g. naphtha, to be intimately contacted with each other either in single stage batch equipment,.

orpreferably in multiple stage counter-current equipment such as columns and permitting proper separation of the immiscible phases to take place. The manner of introduction of any one component may vary to fit best operating techniques.

The invention has been described with particularity as it is4 applied to the preparation of substantially pure sterols from tall oil. However, thev preparation of substantially pure sterols from wool, fat, sh oils (body or liver) andother materials' containing sterols in adrnixture with.

higher alcohols is contemplated.

We claim:

l. Iny a process of obtaining sterols of to purity from a concentrate of said sterols containing about 20 to 50% thereof in admixture` with higher alcohols, which is the same as that obtained by saponifying the rosinl acids and' fatty acids of tall oil and extractingY out the unsaponiable matter from a water and isopropyl alcohol solution thereof' with naphtha, the stepsrwhich. comprise dissolving said' concen tratein naphth'a,` extracting thenapht-hasol'u' tion with furfural 4to remove' the sterols, then removing the furfural from the extracted material.

2. A process of obtaining sterols of 90 to 100% purity from a concentrate of said sterols containing about 20 to 50% thereof in admixture with higher alcohols which is the same as that obtained by saponifying the rosin acids and fatty acids of tall oil and extracting out the unsaponifiable matter from a water and isopropyl alcohol solution with naphtha, which process comprises dissolving said 'concentrate in naphtha, extracting the naphtha solution with furfural to remove the sterols, then removing the furfural and crystallizing the sterols from a solvent.

3. In a process of obtaining sterols of 90 to 100% purity from a concentrate containing about 20 to 50% of said sterols in admixture with aliphatic alcohols containing 20 to 26 carbon atoms in the hydrocrabon nucleus, polymerized rosin components and coloring matter which is the same as that obtained by saponifying rosin acids and fatty acids of tall oil and extracting out the unsaponiiiable matter from a water and isopropyl alcohol solution with naphtha, the steps which comprise dissolving said concentrate in naphtha, extracting the naphtha solution with furfural to remove said sterols and the polymerized rosin components and to leave the higher alcohols in solution in the naphtha, then separating the resultant phases and re-extracting the furfural phase with naphtha to remove the sterols and to leave in solution in the furfural the polymerized rosin components, then evaporating the naphtha.

4. A process of obtaining sterols of 90 to 100% purity from a concentrate consisting of unsaponifiable matter of tall oil and containing about 20 to 50% of said sterols in admixture with aliphatic alcohols containing 20 to 26 carbon atoms in the hydrocarbon nucleus, polymerized rosin components and coloring matter which process comprises dissolving said concentrate in naphtha, extracting the naphtha solution with furfural to remove said sterols and the polymerized rosin components, and to leave the higher alcohols in solution in the naphtha, then separating the resultant phases and re-extracting the furfural phase with naphtha to remove the sterols and to leave in solution in the furfural the polymerized rosin components, then evaporating the naphtha and crystallizing the sterols from an appropriate solvent.

5. In a process of obtaining sterols of 90 to 100% purity from a concentrate thereof containing from 20 to 50% of said sterols in admixture with aliphatic alcohols containing 20 to 26 carbon atoms in the molecular chain together with polymerized rosin components, said concentrate being the same as that obtained by saponifying the rosin acids and the fatty acids of tall oil with alkali and then extracting out the unsaponiable matter from a water-isopropyl alcohol solution thereof with naphtha, the steps which comprise countercurrently kiiowing a solution of said concentrate in naphtha through furfural selectively to dissolve out a higher 'concentrate cf said sterolsA and to leave in solution the alcohols, then removing the furiural from the solution of sterols.

6. A process of obtaining sterolsoi 90 to 100% purity from a concentrate consisting of the unsaponiable matter of tall oil and containing 20 to 50% of said sterols in admixture with aliphatic alcohols of 20 to 26 carbon atom chain length and polymerized rosin components which process comprises countercurrently flowing furfural through a naphtha solution of said unsaponiable matter to obtain two liquid phases, one comprising naphtha containing the higher alcohols, the other containing furfural containing the sterols and the polymerized rosin components, separating the phases and further washing the furfural phase with naphtha in countercurrent flow to remove the sterols and to leave in solution in the furfural the polymerized rosin components, then evaporating the naphtha from the sterol components and recrystallizing said sterol components from an appropriate solvent.

7. A process of obtaining sterol of substantially to 100% purity from a mixture comprising 20 to 50% of sterol and alcohols of 20 to 26 carbon atom chain length, polymerized rosin, coloring matter and the like. the mixture being the same as that resulting from the saponication with alkali of the rosin acids and fatty acids of tall oil followed by extraction of the unsaponiable matter from a water-alcohol solution of the mixture with naphtha which process comprises dissolving the mixture in naphtha in a ratio of 1 part of said mixture per 3 to 100 parts by volume of naphtha, then extracting said solution with furfural in a ratio of 3 to 40 parts by volume per part of solution separating the resultant phases and recovering the sterol from the furfural phase.

8. A process of obtaining sterol of a purity of 90 to 100% from a crude mixture comprising 20 to 50% of sterol together with aliphatic alcohols of 20 to 26 carbon atom chain length, polymerized rosin components and coloring matter and consisting of unsaponiable matter of tall oil, which process comprises dissolving the crude mixture in naphtha in a proportion of one part of crude mixture to 3 to 100 parts of naphtha, then counter'currently extracting the resultant solution with furfural in a proportion of 3 to 40 parts per part of the crude mixture,'separating the resultant phases, recovering sterol and the polymerized rosin components from the furfural phase and re-crystallizing the mixture of sterol and polymerized rosin components from an appropriate solvent of sterol.

9. A process of obtaining a sterol of 90 to 100% purity from a crude mixture containing 20 to 50% of sterol, alcohols of 20 to 26 carbonatom chain length polymerized rosin components and coloring matter said mixture being the same as that resulting from the saponication of the rosin acids and the fatty acids of tall oil and subsequently extracting the unsaponiable matter from a water-isopropyl alcohol solution with naphtha as a solvent, which process comprises dissolving the crude mixture in naphtha in a proportion of one part of the crude mixture to 3 to 100 parts of naphtha, then countercurrently extracting the resultant solution with furfural in a proportion of 3 to 40 parts per part of crude mixture, effecting separation of the furfural and naphtha phase and recovering the sterol from the iurfural phase by extraction of furfural phase with naphtha.

10. A process of obtaining sitosterol of 90 to purity from a crude mixture consisting of unsaponiable matter derived from tall oil containing 20 to 50% of sitosterol, higher alcohols polymerized rosin components and coloring matter, and other constituents which process comprises dissolving the crude mixture in naphtha,

the mixture being in a proportion of 1 part byl volume to 0.5 to 100 parts-by volume of naphtha, this solution being flowed into a vertical column near the midpoint thereof and an additional 0.5 to 100 parts by volume' of naphthaY per part of unsaponifiable matter beingk introduced near the bottom of the column, then countercurrently extracting the solution in the column with furfural in a proportion of 3 to 200 parts by volume per part by volume of crude unsaponiable material, effecting phase separation of the furfural and the naphtha solution, then further extracting the furfural solution by introducing it at the top of a second column and allowing to flow downwardly countercurrently to an upward now of naphtha, the naphtha being in a proportion of 6 to 150 parts by volume of the original unsaponiiiable matter, and removing the solvents from the products.

ll. A process as dened in claim l in which the first mentioned column is operated at a temperature of 60 to 160 F.

l2. A process of obtaining substantially pure sitcsterol from a concentrate of unsaponiable matter comprising it in admixture withlong'chain alcohols, saidl concentrate being the same as that resulting from the extraction of unsapo-niable matter of tall oil from a water and isopropyl alcohol solution of tall oil, the acids of which have been saponied with alkali, the steps which comprise counter-currently flowing naphtha and furiural in the presence of said unsaponiiiable matter to obtain a furfural phase containing the sitosterol and a naphtha phase containing the long chain alcohols, separating the phases evaporating the furfural from the sitosterol and. crystallizing the sitosterol from a solvent thereof.

13. In a process of obtaining sterols of a purity oi 90 to 100% from a mixture of saidv sterols and higher alcohols containing to 50% of sterols and consisting of unsaponiable matter of tall oil, the steps comprising distributing the mixture in a counter-currently flowing system of naphtha and furfural in which the furfural is in a ratio substantially in excess of the naphtha in order selectively to dissolve out most of the sterols in the furfural phase and most of the alcohols in the naphtha phase separating the phases and extracting the furfural phase with naphtha in a second system in an amount to dissolve out most of the sterols contained therein.

14.. In a process of obtaining sterols of a purity of 00 to 100% from a mixture of said sterols and higher alcohols containing 20 to 50%. of sterols and consisting of unsaponiable matterv of. tall oil, the steps comprising distributing the mixture in a counter-currently flowing system. of naphtha and furiural, the ratio of naphtha to furfural being within a range of l to 3 and 1V to '7 parts by volume whereby selectively to dissolve out most of the sterols in the furfural phase and to dissolve most of the alcohols in the naphtha phase separating the furfural phase and extracting most of the sterols from the naphtha phase by contacting the solution oi sterols and furiural -with naphtha in a second system in which the ratio of furfural to naphtha is within the range of l to .5 and l to 2.

15. A process as denecl in claimV 14 in which the proportion of unsaponiable matter to furfnral in the iirst system being within a range of l to 3 and 1 to 140 parts by volume and in the second system the proportion of unsaponiiiable matter upon the basis of the total unsaponiable matter extracted being within. a range of 1 to 6 and 1 to 15e parts by volume.

16; InY a process of, obtainingsterols of 90 to 100% purityA from a mixture'V consisting of unsaponiable matter of tall oil, said unsaponiable matter comprising the sterols` in admixture with higher alcohols the sterols constituting 20 to 50% of the mixture, the` steps which comprise distributing the unsaponiable matter between a counter-currently flowing system of intimately contacting furfural and a nonpolar solvent of the higher fatty alcohols immisciblel with the furfural, separating the solvent phases and removing the solvents from the solutions of sterols and higher alcohols so obtained.

17. In a process of obtaining sterols of' 90 to 100% purity from a mixture consisting ofthe unsaponiable matter of tall oil obtained by preliminary crystallization of the unsaponiiiable matter of tall oil comprising sterols in admixture with higher alcohols, the steps which comprise distributing the unsaponiable matter between a system of' intimately contacting but countercurrently flowing furfural and naphtha: whereby to dissolve most of the sterols in. the furfural phase and most of, the higher alcohols in the naphtha phase separating the sterols from the furfural phase re-dissolving the sterols' in a solvent therefore and crystallizing them out in highly purified state.

18, In a process of obtaining sterols of to purity from a mixture consisting of the unsaponiable matter from tall oil containing sterols and higher alcohols the sterols constitoting 20 to 50% ofthe material, the steps which comprise introducing the unsaponiiiable matter into a column near its midpoint, flowing furfural into the column near the top and naphtha into the column near the bottom; drawing off the naphtha phase at the top as a raiinate and the furfural phase near the bottom as an extract containing most of the sterols, then separating the solvents from the resultant phases.

19. In aprocess of` obtaining sterols of 90v to 100% purity from a mixture consisting of the unsaponiable matter from tall oil comprising said sterols and higher alcohols, the steps which comprise introducing the unsaponiable matter into a column near its midpoint flowing furfural into the column near the top and naphtha into the column near the bottom, drawing on the naphtha phase at the top as a raffinate and the furfural phase near the bottom as an extract containing most of the sterols, then separating the solvents from the resultant phases then further selectively extracting the sterols from the furfural phase by counter-currently contacting said phase with naphtha in a. second column.

20. In a process of obtaining sterols of 90 to 100% purity from `a mixture consisting of the unsaponiable matter from tall oil containing the sterols in admixture with higher alcohols the sterols constituting 20 to 50% of the mixture, the steps which comprise introducing the unsaponifable matter into a column near its midpoint, iiowing furfural into the column near the top and naphtha` into the column near the bottom, the unsaponiable mattei:l being. inV a proportion of 1 part to 3 to 100 parts of naphtha, drawing oi the naphtha phase containing most of the alcohols at the top as a rainate and the furfural phase near the bottom as an extract, containing most of the sterols, then separating the solvents fromA the phases.

2l. In a process of obtaining sterols of 90 to 100% purity from a mixture vconsisting ofthe unsaponifable matter from tall oil containing 20 to 50% of said sterols admixed with higher vtop and naphtha into the column near the bottom, the temperature within the column being maintained within the range of 60 to 160 F. drawing oi a solution of higher alcohols and naphtha at the top of the column as a raffinate and a solution of sterols and furfural as an extract at the bottom, then separating the solvents from the resultant phases.

22. In a-process of obtaining sterols of 90 to 100% purity from unsaponiable matter of tall oil comprising said sterols in admixture with higher alcohols the sterols constituting 20 to 50% of the mixture, the unsaponiable matter being the same as that resulting from the saponiiication of the rosin acids and the fatty acids of tall oil and subsequently extracting the unsaponiable matter from a water-isopropyl alcohol solution thereof with naphtha as a solvent of the unsaponifiable matter the steps which comprise introducing the unsaponifiable matter into a column near its midpoint, flowing furfural into the column near the top and naphtha into the col umn near the bottom, the temperature within 14 tall oil comprising 20 to 50% of sterols in admixture with higher alcohols, the steps which comprise mixing material consisting of the unsaponifiable matter of tall oil with naphtha, introducing the unsaponiable matter containing naphtha into a column near its midpoint, flowing iurfural into the column near the top and additional naphtha into the column near the bottom, drawing off the naphtha phase containing the higher alcohols at the top as a raffinate and the furfural phase containing the sterols near the bottom as an extract, then separating the solvents from the resultant phase.

24. In a process of obtaining sterols of to purity from a concentrate consisting of the unsaponiable matter from tall oil, said unsaponiable matter comprising V20 to 50% of sterols in admixture with higher alcohols, the steps which comprise introducing the unsaponiiiable matter admixed with furfural into a column near its midpoint, ilowing additional furfural into the column near the top and naphtha into the column near the bottom, drawing off the naphtha phase at the top as a rainate containing the higher alcohols and the furfural at the bottom as an extract containing most of the sterols then separating the solvents from the resultant phases.

HENRY A. VOGEL. ROGER M. CHRISTENSON.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 2,111,259 Blengsll Mar. 15, 1938 2,240,365 Dreger Apr. 29, 1941 2,363,925 Adams Nov. 28, 1944 

1. IN A PROCESS OF OBTAINING STEROLS OF 90 TO 100% PURITY FORM A CONCENTRATE OF SAID STEROLS CONTAINING ABOUT 20 TO 50% THEREOF IN ADMIXTURE WITH HIGHER ALCOHOLS, WHICH IS THE SAME AS THAT OBTAINED BY SAPONIFYING THE ROSIN ACIDS AND FATTY ACIDS OF TALL OIL AND EXTRACTING OUT THE UNSAPONIFIABLE MATTER FROM A WATER AND ISOPROPYL ALCOHOL SOLUTION THEREOF WITH NAPHTHA, THE STEPS WHICH COMPRISE DISSOLVING SAID CONCENTRATE IN NAPHTHA, EXTRACTING THE NAPHTHA SOLUTION WITH FURFURAL TO REMOVE THE STEROLS, THEN REMOVING THE FURFURAL FROM THE EXTRACTED MATERIAL. 